How severe is this DTC?
Average severity for this, as emission-related faults can truly affect the environment around it. That said, sometimes with emission faults, there will be no symptoms present but can still have repercussions if left unaddressed.
What are some of the symptoms of the code?
Symptoms of a P2206 diagnostic code may include:
- Failed emissions test
- Intermittent CEL (Check Engine Light)
What are some common causes of the code?
Causes
of this P2206 cruise control code may include:
- Faulty NOx sensor
- Faulty NOx sensor heater
- Internal opening in the ECM (Engine Control Module) or the NOx sensor itself
- Water intrusion
- Broken connector tabs (intermittent connection)
- Melted harness
- Dirty sensor element
- High resistance present in the heater control circuit
What are the diagnostic and troubleshooting steps for P2206?
The first step in the troubleshooting process for any malfunction is to check the Technical Service Bulletins (TSBs) for known issues with the specific vehicle.
Advanced diagnostic steps become very vehicle-specific and may require the appropriate advanced equipment and knowledge to operate accurately. We include the basic steps below, but refer to a repair guide specific to the year/make/model/drivetrain for steps tailored to your vehicle.
Basic Step #1
Most NOx sensors used in automotive and diesel truck applications will be quite accessible. Given this fact, keep in mind that they can be extremely stubborn to remove with all the expansion and contraction that occurs with temperature fluctuations in the exhaust system. So, make sure you need to remove the sensor before doing so. Most sensor tests should be able to be performed from the connector. Refer to your service manual for pinpoint tests of the NOx sensor to obtain the desired values.
NOTE: You may need to use some heat when replacing the NOx sensor to avoid stripping the threads of the exhaust plug. Penetrating oil is always a good idea whenever you think you might remove the sensor in the near future.
Basic Step #2
Follow the harness involved with the NOx sensor to assess its condition. Most of the time, harnesses will be run near the extreme heats mentioned earlier. So, keep a close eye out for melted harnesses or connectors. Be sure to repair any chafing or damaged harnesses to prevent future malfunctions.
Basic Step #3
Visually inspect the exhaust system, especially the interior, to determine if there is enough soot present that could potentially harm the overall functionality of the sensor. Generally speaking, diesel engines produce an abnormal amount of soot anyway. That being said, aftermarket tuner upgrades can affect the fuel mixture and create above-normal amounts of soot, which can consequently lead to premature NOx sensor failure, given the richer fuel mixtures involved with some aftermarket tuners. Make sure to clean the sensor if you suspect this is the case and return the fuel mixture to normal OEM specifications by removing or disabling the tuner.
Basic Step #4
Finally, if you have exhausted your resources and still cannot identify the issue, it would be a good idea to locate your ECM (Engine Control Module) to check for water intrusion. Sometimes, inside the vehicle, it can be prone to creating moisture inside over time (e.g., heater core leak, window seal leak, melting residual snow, etc.). If significant damage is found, it will need to be replaced. To do this, in most cases, the new ECM will need to be reprogrammed for the vehicle to ensure a seamless adaptation. Unfortunately, generally speaking, dealerships will be the only ones equipped with the appropriate programming tools.
This article is strictly for informational purposes only, and the technical data and service bulletins for your specific vehicle should always take precedence.